You will need to check the properties of your CD-ROM drive under Device Manager. To get to it, right click My Computer and click on Properties. Click on the Device Manager tab. Click on the plus sign next to CDROM and click on your CD-ROM drive. Now, click on the Properties button at the bottom of the windows, which should give you the properties of your CD-ROM drive. Click on the Settings tab.
Now, reverse the check mark in the DMA setting - set it back to what it was before. Then, make sure the "auto insert notification" has a check mark. Then, click OK/OK, and see if this solves your problem.